An active matrix device, such as described in U.S. Pat. No. 6,469,684, comprises an inversion circuitry coupled to drive signals, which inversion circuitry has at least one Cole sequence generator providing random, semi-random, or pseudo-random sequence patterns of the matrix. The Cole sequence generator provides a sequence of inversion patterns of pixel biasing over several frames. Over time each pixel is presented with a substantially equal number of positive and negative drive levels to prevent the generation of undesirable display artifacts, such as image retention or image sticking, that might occur under a direct current bias without inversion.
Generally for television applications, this pixel biasing inversion is carried out once per frame, that is, with a frequency equal to a display refresh rate and synchronous with a video signal. For the reduction of motion artifacts, often a scanning backlight is applied as light source for a liquid crystal display panel. The light of lamps of the scanning backlight is generally emitted in the form of light pulses. If the repetition rate of these pulses is rather low, for example in the order of 50 to 60 Hz, an undesirable flicker is visible due to these light pulses. The inventors have observed that, when increasing the display frame rate to solve this problem, other artifacts deteriorate the quality of the images displayed on the display panel.